fix: remove lm_head for granite with llama arch models (#258)

* initial code for deleting lm_head

Signed-off-by: Anh-Uong <anh.uong@ibm.com>

* fix logic for copying checkpoint

Signed-off-by: Anh-Uong <anh.uong@ibm.com>

* fix check that embed_tokens and lm_head weights are the same

Signed-off-by: Anh-Uong <anh.uong@ibm.com>

* fix warning assertion

Signed-off-by: Anh-Uong <anh.uong@ibm.com>

* fix lm_head check, remove test

Signed-off-by: Anh-Uong <anh.uong@ibm.com>

* small fixes from code review

Signed-off-by: Anh-Uong <anh.uong@ibm.com>

* fmt

Signed-off-by: Anh-Uong <anh.uong@ibm.com>

---------

Signed-off-by: Anh-Uong <anh.uong@ibm.com>
Co-authored-by: Anh-Uong <anh.uong@ibm.com>

Author: Ssukriti

build/accelerate_launch.py

@@ -26,9 +26,13 @@
 import tempfile
 import shutil
 from pathlib import Path
+import json
 
 # Third Party
 from accelerate.commands.launch import launch_command
+from transformers import AutoModelForCausalLM, AutoTokenizer
+from peft import PeftModel
+from torch import bfloat16
 
 # Local
 from build.utils import (
@@ -44,10 +48,18 @@
     USER_ERROR_EXIT_CODE,
     INTERNAL_ERROR_EXIT_CODE,
 )
+from tuning.data import tokenizer_data_utils
 
 ERROR_LOG = "/dev/termination-log"
 
 
+def get_base_model_from_adapter_config(adapter_config):
+    """Given path to adapter_config.json file, returns the base model name"""
+    with open(adapter_config, "r", encoding="utf-8") as config_file:
+        adapter_config = json.load(config_file)
+        return adapter_config.get("base_model_name_or_path")
+
+
 def main():
     LOGLEVEL = os.environ.get("LOG_LEVEL", "WARNING").upper()
     logging.basicConfig(level=LOGLEVEL)
@@ -118,16 +130,89 @@ def main():
             sys.exit(INTERNAL_ERROR_EXIT_CODE)
 
         try:
-            # copy last checkpoint into mounted output dir
-            pt_checkpoint_dir = get_highest_checkpoint(tempdir)
-            logging.info(
-                "Copying last checkpoint %s into output dir %s",
-                pt_checkpoint_dir,
-                original_output_dir,
-            )
-            copy_checkpoint(
-                os.path.join(tempdir, pt_checkpoint_dir), original_output_dir
+            last_checkpoint_dir = get_highest_checkpoint(tempdir)
+            last_checkpoint_path = os.path.join(tempdir, last_checkpoint_dir)
+
+            use_flash_attn = job_config.get("use_flash_attn", True)
+            adapter_config_path = os.path.join(
+                last_checkpoint_path, "adapter_config.json"
             )
+            tokenizer = AutoTokenizer.from_pretrained(last_checkpoint_path)
+
+            if os.path.exists(adapter_config_path):
+                base_model_path = get_base_model_from_adapter_config(
+                    adapter_config_path
+                )
+                base_model = AutoModelForCausalLM.from_pretrained(
+                    base_model_path,
+                    attn_implementation="flash_attention_2" if use_flash_attn else None,
+                    torch_dtype=bfloat16 if use_flash_attn else None,
+                )
+
+                # since the peft library (PEFTModelForCausalLM) does not handle cases
+                # where the model's layers are modified, in our case the embedding layer
+                # is modified, so we resize the backbone model's embedding layer with our own
+                # utility before passing it along to load the PEFT model.
+                tokenizer_data_utils.tokenizer_and_embedding_resize(
+                    {}, tokenizer=tokenizer, model=base_model
+                )
+                model = PeftModel.from_pretrained(
+                    base_model,
+                    last_checkpoint_path,
+                    attn_implementation="flash_attention_2" if use_flash_attn else None,
+                    torch_dtype=bfloat16 if use_flash_attn else None,
+                )
+            else:
+                model = AutoModelForCausalLM.from_pretrained(
+                    last_checkpoint_path,
+                    attn_implementation="flash_attention_2" if use_flash_attn else None,
+                    torch_dtype=bfloat16 if use_flash_attn else None,
+                )
+
+            model_arch = model.config.model_type
+            # check that it is a granite model with llama architecture with tied weights
+            # ie. lm_head is duplicate of embeddings
+
+            # a fine tuned model will have params_dict.get("model.embed_tokens.weight")
+            # a prompt adapter has params_dict.get("base_model.model.embed_tokens.weight")
+            # a lora adapter has params_dict.get("base_model.model.model.embed_tokens.weight")
+            copy_checkpoint_bool = True
+            if model_arch == "llama" and hasattr(model, "lm_head"):
+                if (
+                    # lora tuned model has an addt model layer
+                    (
+                        hasattr(model.model, "model")
+                        and model.lm_head.weight.untyped_storage().data_ptr()
+                        == model.model.model.embed_tokens.weight.untyped_storage().data_ptr()
+                    )
+                    # prompt tuned model or fine tuned model
+                    or (
+                        hasattr(model.model, "embed_tokens")
+                        and model.lm_head.weight.untyped_storage().data_ptr()
+                        == model.model.embed_tokens.weight.untyped_storage().data_ptr()
+                    )
+                ):
+
+                    copy_checkpoint_bool = False
+                    logging.info("Removing lm_head from checkpoint")
+                    del model.lm_head.weight
+
+                    if hasattr(model, "lm_head.weight"):
+                        logging.warning("Failed to delete lm_head.weight from model")
+
+                    logging.info("Saving checkpoint to %s", original_output_dir)
+                    model.save_pretrained(original_output_dir)
+                    # save tokenizer with model
+                    tokenizer.save_pretrained(original_output_dir)
+
+            # copy last checkpoint into mounted output dir
+            if copy_checkpoint_bool:
+                logging.info(
+                    "Copying last checkpoint %s into output dir %s",
+                    last_checkpoint_dir,
+                    original_output_dir,
+                )
+                copy_checkpoint(last_checkpoint_path, original_output_dir)
         except Exception as e:  # pylint: disable=broad-except
             logging.error(traceback.format_exc())
             write_termination_log(